在TOFD非平行扫查检测中, 是假定缺陷位于焊缝中心轴线上的。因此对于偏离焊缝中心轴线的缺陷, 其埋藏深度和自身高度这两个方位参数的测量存在一定的误差。通过数学推导, 建立了相应的数学模型, 从理论上分析了埋藏深度、自身高度、偏心距大小、探头入射点间距等多个因素对该误差影响的变化规律, 并通过试块进行了试验验证。结果证明减小埋藏深度及高度测量误差的方法对TOFD无损检测工艺的选择具有较好的指导意义。

It is assumed that the defect is located in the center of the weld in parallel scan by TOFD, so the measurement of orientation parametters such as depth and height has some errors as for the axis deviation defects in weld. Through accurate mathematical deduction, the article establishes detailed mathematical model so as to analyze the changes regulation of measurement error of depth and height by various factors (such as true depth, true height, axis deviation, probe center separation),and experimental verification by TOFD block is carried out; meanwhile, the article proposes the methods of reducing the measurement error, and they have great guiding significance for process selection of TOFD nondestructive testing.